A US citizen jailed in Iran said in a letter released Wednesday that his captors were keeping him in harsh conditions in hopes of obtaining a prisoner swap. Amir Mirzai Hekmati, a former Marine who holds dual citizenship, said he was kept in...

US Secretary of State John Kerry on Wednesday called for the release of two American dual citizens jailed in Iran, saying Washington was “deeply concerned” about their fate. He also again requested information on an American who went...